1. Field of the Invention
The present invention relates to a process for producing 1,3-di-(2-hydroperoxy-2-propyl)benzene (hereinafter, referred to as "DHPO"). More particularly, the present invention relates to a process for producing DHPO, said process allowing successful solution of problems that a by-product, 1,3-di-(2-hydroxy-2-propyl)benzene (hereinafter, referred to as "DCA") causes inconveniences such as occlusion of inside space of an apparatus and failure of detection of measuring machines and that such inconveniences makes a long-term safe operation difficult.
2. Background Information
There has been known a process in which a starting solution containing 1,3-diisopropylbenzene (hereinafter, referred to as "MDC") is subjected to an oxidizing reaction to convert MDC into DHPO and DHPO is then subjected to acid cleavage reaction to produce resorcinol and acetone. The oxidized solution produced contains DHPO, 3-(2-hydroxy-2-propyl)-1-(2-hydroperoxy-2-propyl)benzene (hereinafter, referred to as "CHPO"), 3-isopropyl-1-(2-hydroperoxy-2-propyl)benzene (hereinafter, referred to as "MHPO"), unreacted MDC and a by-product, DCA. Said oxidized solution is subjected to an extraction using an aqueous alkali solution or the like to produce an aqueous layer containing mainly DHPO and CHPO and an oily layer containing mainly MHPO, MDC and DCA. At least part of said oily layer is usually recycled as a circulating oil to the oxidizing reaction step in order to recover MHPO and MDC. In the conventional technique, however, problems arose that DCA as the by-product precipitated at various parts of the system causing inconveniences such as occlusion of inside space of an apparatus and failure of detection of measuring machines and that such inconveniences makes a long-term safe operation difficult.
After extensive studies searching for a process for producing DHPO having no such problems, the present inventors have found that the inconveniences such as occlusion of the inside space of the apparatus and failure of detection of measuring machines does not arise by maintaining the accumulated equilibrium concentration of 1,3-di-(2-hydroxy-2-propyl)benzene (DCA) in the circulating oil at 4.2% by weight or less when the oxidized solution obtained by subjecting the starting solution containing MDC to the oxidizing reaction is subjected to an extraction using an aqueous solution and at least part of the oily layer is recycled as a circulating oil to the starting solution. The present invention has been completed on the basis of such fact.